Ingot



INGOT f original Filed Aug. 12, 1929 l l y v C 6 C f 6 f Patented Mar. 15, 1932 UNITED STATES PATENT OFFICE LEWIS GERALD FIRTH, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO FIRTH- STERLING STEEL COMPANY, OF MCKEESPORT, PENNSYLVANIA, A CORPORATION F PENNSYLVANIA :Noor

Original application led August 12, 1929, Serial No. 385,255. Divided and this application led August 16. 1930. Serial No. 475,721,

a central body portion of relatively porous now usually cast in molds having a substanmetal and well deiined longitudinally severable flanges of relatively non-porous metal extending from the body portion. v

Ingots of steel or other metals or alloys are tially square cross-section. The ingot molds are sometimes provided With hot-tops through which the metal is poured into the mold, the hot-tops being used to keep the metal in liquid condition, thereby tending to decrease the amount of shrinks, pipes, and porosity ofthe cast ingot. Even with the use of hot-tops, however, the ingots are somewhat porous and for certain purposes it is necessary to scrap a large proportion of the in ot and use only that portion of the ingot w lich is substantially entirely free from porosity, segregation and shrinks. In making pistons incr pneumatic rock-drills, valve seats and valves which are to be subjected to great pressures, or for airplane Work, or other similar usages, it is necessary that the metal be substantially free from defects'such as segregation, shrinks, or porous structure.

My invention is particularly adapted Where it is necessary that the ingot be substantially free from the defects above mentioned. The usual process of casting ingots as practiced at the present time is to pour in such a Way that the last portion to cool is at the top ofl the ingot and may be discarded. However, in any given lcross section of an ingot at right angles to its longitudinal axis, the last portion to cool is the extreme '.center. It is probable that the central 5% to 15% of this cross section cools almost simultaneously, i. e., the solidification is progressive from the sides of the .mold up to a certain point, at which point more or less simultaneous freezing takes place. It is this central 5% to 15% which contains the greater part of the segregated impurities and gases. This central portion also usually cools progressively from the bottom of the ingot to the top and it is customary to discard the upper portion or pipe end which, generally speaking, is the last portion to cool. It is impracticable, however, under present practice to discard the Whole of that central axis or core which extends from the bottom to the .top of the ingot and which contains the steel last to cool Ain each horizontal' plane.

In my invention, I not only discard the top portion of the ingot, according to common practice, but I also sever the ingot longitudinally and discard that portion in each horizontal plane which was the last to cool. It is in this respect that my invention differs radically from present dayI practice. The approximate amount of this'l'ast cooled portion to be removed according to my process is from 10% to 30% of the original weight of the ingot, this being taken mainlyfrom the central portion of the casting. When a very high degree of perfection is required, as much as 50% of the original Weight may be removed from the central portion. This c an be regulated by cutting the ingot nearer or further from its central axis.

In my reference to horizontal planes and longitudinal axis I refer to ingots cast upright according to the usual practice, but my invention can also be applied when the ingot is cast with the longitudinal axis sloping or horizontal, 4and using either top or bottom pouring, or a combination of both. In accordance with my invention, the ingot 1s cast in a mold having deep recesses formed therein Which form flanges on the ingot extending outwardly from the body portion of the ingot. Any shrinks, pipes, or porous structure Which may be present in the ingot are in the central portion thereof, and the ianges are free from such defects. The flanges are then separated lfrom the relatively porous body portion and are Worked by rolling or other shaping methods to form the desired articles.

This application isA a division of my Patent No. 1,7 92,581, granted February 17, 1931.

- Various shaped ingot molds are now employed to produce ingots which have a decreased tendency When rolled to form corner cracks and surface cracks. One type of such ingots has the cross sectional shape of a being joined by inwardly bellied secondary corner walls. Such an ingot mold is described in Gathmann Patent, No. 1,719,543 and is designed to decrease corner and surface cracks when rolling large ingots.

The ingot mold of the present invention differs from that described in the above referred to Gathniann patent or from similar types by the fact that in the present invention the ingot mold is provided with deep recesses in its molding surfaces for forming well defined flanges which may be severed from the body portion of the ingot, and the severed flanges may thereafter be formed into the desired article. Any recesses formed in the ingot mold according to the Gathmann patent above referred to are merely incidental to producing a contour of ingot such that corner cracks and surface cracks will be reduced when the ingot is rolled. The recessesin the ingot mold are not of sufllcient depth to provide well defined flanges which can be severed longitudinally from the body of the ingot and formed into the desired article.

In the accompanying drawings, which illustrate several present preferred embodiments of my invention;

Figure 1 is an elevation of an ingot mold;

Figure 2 is a section on the line II-II of Figure 1; showing the ingot in the mold;

Figures 3 and 4 are sections similar to Figure 2, but showing ingots having four and five flanges, respectively;

Figure 5 is a section similar to Fi ures 2, 3 and 4, but showing another modi cation;

Figure 6 is a horizontal section of one of the flanges formed on the ingot, after the flange has been separated from the body portion of the ingot; and

Figure 7 is a perspective view of a rockdrill piston.

Referring more particularly to Figures 1 and 2 of the drawings, there is shown an ingot mold 2 which is generally triangular in shape. The mold is formed of sections 3, 4 and 5, which are bolted together by bolts 6 and nuts 7. The mold provides deep recesses 8 extending radially from a central recess 9 which forms the body portion of the ingot. The recesses 8 taper outwardly from the central portion of the mold, for a purpose hereinafter described.

In casting an ingot in the illustrated mold, the metal is poured in] the usual manner, preferably through a hot-top. The metal flows into the recesses 8 to form an ingot having a central body portion 10 and flanges 11 extending therefrom. Each of the flanges 11 has its three outer sides cooled bythe mold. The side of the flange 11, which is connected to the central portion 10 of the ingot, remains hot for a longer time than the other sides of the flanges which contact with the mold sections. The cooling action of the ingottakes place first on the sides exposed to the mold sections so that the flanges 11 are formed without shrinks, porous spots, or segregation. The only porous portion of the ingot is the central portion 10.

The flanges 11 are then separated along the lines 15 from the central portion of the ingot which was the last portion to cool. After separation, the flanges, which are entirely solid, are rolled, forged, or otherwise shaped into the desired articles.

The ingot shown in Figure 3'is similar to the ingot of Figure 2, except that in Figure 3 the ingot has four flanges 11a instead of three. An ordinary mold 20 of substantially square cross section can be converted into a mold embodying my invention by inserting filler blocks 21 in the corners of the mold in order to form a moldy having recesses 8a which form flanges 11a on the body portion of the ingot, a body portion being that portion of the ingot enclosed by the dotted lines 15a. l/Vhen the mold shown in Figure 3 i`s used for casting the ingot, the flanges 11a are separated along the lines 15a from the central portion of the ingot.

In Figure f there is shown a mold having five recesses 8b, which form an ingot having five flanges 11b extending radially therefrom. My invention contemplates the formation of an ingot having any number of flanges formed thereon.

In Figure 5 another form of ingot mold is shown. This mold has recesses 8c formed therein, which form the flanges 110 on the ingot. It also has recesses 25 provided in the mold which form flanges 26 on the ingot. When a mold of this shape is employed, the flanges 8c are separated from the remainder of the ingot along the lines 150 and only the two flanges 110 are worked to form the desired articles. The recesses 25 in the mold and the corresponding flanges 26 formed on the ingot are provided in order to cause the shrinks and segregations to'take place as indicated at 27, and in order that the flanges 11e will be free from such defects.

In each of the embodiments, the flanges are separated by well defined recesses extending inwardly to points close to the body portion of the ingot. Thus, for example, in the embodiment shown in Figure 3, the flanges 11a are separated by well defined recesses 40a formed by the filler blocks 21. The recesses 40a extend close to the body portionfof the ingot, which is that portion enclosed by the dotted lines 15a.

The illustrated molds are made in sections which are bolted together, but, if desired, solid molds may be employed instead of split molds, and any number of recesses may be provided in the molds to form a corresponding number of flanges on the ingots.

The recesses 8, 8a, 8b and 8c, preferably slope outwardly from the central portion of the mold. In Figure 6 there is illustrated a flange 11 formed in the mold illustrated in VFigure 2. As above stated, the flanGeS 11 are substantially free from porosity andasegregation. However, there is a small portion 12 of the flange which is not quite as dense as the remainingT portion of the flange. This is due to the fact that the portion 12 is the last to cool. In order to make the density of the billet rolled from the flange 11 absolutely uniform, the flanges are cast having a slight taper outwardly from the central portion of the ingot. The inner portion 30 of the flange accordingly is subjected to greater work than the outer portion 3l when the flange is rolled. 'l` he greater amount of work to which the portion 30 is subjected gives the rolled billet substantially uniform density throughout.

After rolling, forging, or otherwise shaping the flange 11, it is formed into the desired article.

A piston 35 for a rock-drill is illustrated in Figure 7 Pistons made according to my invention are free from porosity, shrinks, and other defects and are particularly adapted for the work which they have to perform. If a piston for a rock-drill is slightly porous. it is likely to crack under the strain imposed by the terrific impactl of the piston against the other parts of the rock-drill.

My invention is especially useful in the production of alloy steel articles which are expensive and in which it is desired to reduce to a minimum the portion of the ingot which it is necessary to discard because ofits porous character.

If desired, the ingot may be cast into molds which are rotated in order to force the metal from the central portion of the mold into the recesses which form the flanges on the ingot.

I have illustrated and described several preferred forms of the invention. It is to be understood, however, that the invention may be otherwise embodied within the scope of the following claims. Y

I claim:

1. An ingot having a.. body portion, and at least three well defined severable flanges projecting outwardly beyond the bod portion for a substantial distance, the anges being separated by well defined recesses extending inwardly to points close to the body portion, the flanges being substantially free from segregation, shrinks, and pipes, the volume of the metal in the flanges being greater than the volume of metal in the body portion.

2. An ingot having a body portion, and at least three well defined severable flanges projecting outwardly beyond the body poryWardly bey tion for a substantial distance, the flanges being separated by well defined recesses extending inwardly to points close to the body portion, the flanges tapering outwardly from the body portion, the volume of the metal in the flanges being reater than the volume of metal in the bo y portion.

3. An ingot having a body portion, and well defined severable flanges projecting outond the body portion for a substantial d1stance at angles of substantially 120, the flanges being separated by well delined recesses extendmg inwardl to points close to the body portion, the vo ume of the metal in the flanges being greater than the volume of metal in the body portion.

4f. An ingot having a body portion, and well defined severable flanges projecting outwardly beyond the body portion for a substantial distance, the flanges being separated by well defined recesses extending inwardly to points close to the body portion, the cross section of the ingot in a plane transverse to its longitudinal axis being substantially cruciform, the flanges being substantially free from segregation, shrinks and pipes,the volume of the metal in the flanges being reater than the volume of metalin the bo y portion.

In testimony whereof, I have hereunto set my hand. i

LEWIS GERALD FIRTH. 

